There are several know devices where a shaft is rotated by the pushing and pulling movements of the hands, and out of which perhaps the most important applications are vehicles driven by human power, especially three or more wheeled vehicles made for disabled subjects. For sporting purposes there are hand-driven bicycles known, although these are not widely used.
In fitness room there are several fitness machines that use hand power, but in these training devices it is not a task the rotation of a shaft, although on such rotating shafts one can easily mount a braking system.
Finally it should be mentioned that the pushing and pulling movement of hands can be used for driving smaller boats, i.e. such movements can be used for the rotation of a propeller.
The systems used for such applications use the alternating forward and backward movement of the hands, and in a forward-backward cycle only one direction of hand movement is utilized for driving. From ergonomic point of view solutions are more preferred where the two hand move simultaneously forward and backward and exerts then pushing and pulling forces. A typical example of the simultaneous hand movement is rowing, although in such cases only the pulling movement is used for driving the boat because the other direction is used to return the oars to their initial position. When work is done by both hand it is also a significant aspect how far the required force vector fall from the body center in lateral direction. There are drives using both hands, such as described in U.S. Pat. No. 4,705,284 wherein the two handgrips are laterally far away from the line of the shoulders. In such lateral position it is tiring to work, especially to push. In this patent this problem is solved in such a way that the vehicle is driven only in the pulling direction by the handgrips and in the other direction a freewheel mechanism makes the movement free.
An example for working in only one direction can be found in a very old publication of U.S. Pat. No. 1,559,826, wherein two handgrips are use for rotating a boat propeller, but here also only one direction of the movement is useful. The mechanical transmission is resolved here by using a gear-transmission that has a very low efficiency, therefore such solution have not of spread.
From the point of view of exerting forces it is required that the vector of the required force be not outside the position of the shoulders, and such can be even within the should lines.
In case of hand driven vehicles a further problem arises, namely the driving arm used for pushing and pulling require both hands and one has no third hand for steering. There are hand driven vehicles know where the chain driving of bicycles is imitated by hands, wherein the turning of the driving handgrips steer the vehicle. In such cases freely rotating handgrips are required, furthermore it is ergonomically less preferred and more tiring to rotate handgrips and to turn them at the same time when steering is needed as if the task was only pushing and pulling.
The pulling and pushing movement use different muscle groups, and there are subjects that can be loaded in one of these movement direction more than in the other one, therefore there is a need for a solution where the transmission ration for pulling and pushing can be different and can be adjusted independently.
In the international publication WO/2010/084363 a device is described for the alternating driving of bicycles, in which the rotating movement of the pedals is converted into alternating swinging movement, then the alternatingly forward and backward moving of respective swinging arms pull a pair of ropes wound previously to rope drums arranged at both sides of the rear wheel hub, and the required torque is provided by the tangential forces acting on the rope drums.
A preferable design of such rear hubs is described in the international publication WO/2012/001436, in which it is explained that in the interior of the rope drums respective coil springs are arranged that provide for the return movement of the rope drum and for the biasing of the rope when the direction of the movement gets reversed. It is also described in this publication how the respective freewheels have to be arranged in the hub, and a third freewheel is also used that enables the reverse rotating of the driven wheel.
The solutions described in these publications have high efficiency, and the extent of displacement of the ropes in the respective cycles can be adjusted by changing the distance of pulled rope wheels placed on the swinging arms from the axis of rotation.